This invention relates to the configuration and construction of model helicopters. More particularly, this invention relates to a model helicopter fuselage, landing gear, and power train elements that simplify construction and reduce manufacturing costs.
Helicopters are flying machines having the ability to hover and fly forwards, backwards, and sideways. This agility stems from the multiple capabilities of the main rotor system. Since the invention of helicopters in the 1930's considerable effort has been expended advancing helicopter technology, with a substantial percentage of that effort concentrated on main rotor systems.
While the technology of full-size helicopters progressed for decades, model helicopters remained impractical for lack of suitable engines, radio control equipment, and construction materials. Model helicopter designers often copied the designs of full-size helicopters without understanding the basic differences between full size and model aircraft. As a result, scaled-down model helicopters were typically unstable and underpowered.
In the 1970's hobbyists developed the first practical model helicopters. Lighter radio control equipment, more powerful engines, and systematic engineering all contributed to early successes. Much of model helicopter design, however, is rooted in tradition. Even though helicopter technology has advanced considerably since that time, the designs and design philosophies of that era are still in widespread use.
Model helicopters currently available are typically complex and expensive. As a result, the market for model helicopters is relatively small. Many helicopter manufacturers cater to wealthy and sophisticated hobbyists in order to sell their products. Although many less affluent hobbyists are interested in helicopters, helicopters are usually beyond their economic means and skill level. Reducing the overall cost and complexity of model helicopters would bring them within reach of a large group of hobbyists.
Much of the complexity and cost of helicopters is concentrated in the main rotor system, but a great deal is added by the basic fuselage structure. The structure of a typical model helicopter fuselage is a framework stamped from aluminum sheet metal or molded of reinforced plastic, and assembled with nuts and bolts. Radio control components such as the battery, receiver, and servos bolt onto shelves or extensions of the framework. Mechanical components such as the engine and drive train are usually mounted inside the framework. Landing gear is typically constructed of aluminum and plastic. All-aluminum landing gear is relatively weak and easily damaged, while plastic landing gear is typically thick and bulky.
While structurally strong, traditional model helicopter fuselage construction often involves assembling many separate pieces with a multitude of fasteners and sometimes adhesives. A particular drawback of metal framework is the tendency of the framework to bend when the model helicopter crashes. Since the fuselage usually must be entirely disassembled to straighten bent framework, repairs to the model helicopter can be very time consuming. Simplified model helicopter fuselage structure has the triple benefit of reducing manufacturing cost, assembly time, and repair time.
Simplified fuselage structure also leads to simplified mounting of the various mechanical components attached to the fuselage. Simplified fuselage structure combined with a well-planned layout for radio system components and engine drive train components can greatly reduce the number of parts in the helicopter and consequently manufacturing cost and assembly time.
Given the cost and complexity of model helicopters currently available, what is needed are simple, sturdy, and light-weight elements for model helicopter structures and drive train components.
In accordance with the present invention, there is provided a model helicopter including an improved fuselage having a central keel structure supporting radio-control system components, mechanical drive train components including a source of motive power, landing gear, canopy, and a tail rotor. This improved fuselage provides a simplified structure for model helicopters.
In preferred embodiments, the fuselage includes a canopy support frame attached to the keel. The canopy fits over and attaches to the canopy support frame to cover the components supported by the keel including the radio-control system components, and the mechanical drive train components.
Advantageously, the fuselage further includes landing gear supports attached to the keel. These landing gear supports are also attached to front and rear landing gear struts which support the model helicopter when it is resting on the ground.
In preferred embodiments of the present invention, the mechanical drive train components include an engine assembly, a gear assembly, and a main rotor shaft for driving a main rotor. It will be understood that the onboard model helicopter engine is started by transferring rotation from a separate starter motor to the model helicopter engine.
Advantageously, the drive train includes an improved starter cone linked to the model helicopter engine that engages the starter motor and transmits the rotation of the starter motor to the engine. This improved starter cone includes a concave side wall capable of centering the starter cone in the starter motor while the starter motor is providing power to the engine.
Additional objects, features, and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.